Tested with a VM disk that has unmapped blocks and that fixes it. On Thu, Feb 15, 2024 at 3:54 PM Nicolas Frayer <nfra...@redhat.com> wrote: > > On Thu, Feb 15, 2024 at 2:51 PM Daniel Kiper <dki...@net-space.pl> wrote: > > > > Adding Marta, Nicolas, Sebastian and Vladimir... > > > > Jon, thank you for the patch! > > > > Marta, Nicolas and Sebastian, may I ask you to run tests with this fix? > > Thanks Jon, Daniel. > Sure, I will give it a try. > I was actually about to send my own version for review. > > > > > Daniel > > > > On Sun, Feb 11, 2024 at 10:34:58AM -0500, Jon DeVree wrote: > > > The directory extent list does not have to be a continuous list of data > > > blocks. When GRUB tries to read a non-existant member of the list, > > > grub_xfs_read_file() will return a block of zero'ed memory. Checking for > > > a zero'ed magic number is sufficient to skip this non-existant data > > > block. > > > > > > Prior to commit 07318ee7e this was handled as a subtle side effect of > > > reading the (non-existant) tail data structure. Since the block was > > > zero'ed the computation of the number of directory entries in the block > > > would return 0 as well. > > > > > > Fixes: 07318ee7e (fs/xfs: Fix XFS directory extent parsing) > > > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2254370 > > > Signed-off-by: Jon DeVree <n...@vault24.org> > > > --- > > > grub-core/fs/xfs.c | 10 ++++++++++ > > > 1 file changed, 10 insertions(+) > > > > > > diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c > > > index bc2224dbb..a6cce9cfe 100644 > > > --- a/grub-core/fs/xfs.c > > > +++ b/grub-core/fs/xfs.c > > > @@ -902,6 +902,7 @@ grub_xfs_iterate_dir (grub_fshelp_node_t dir, > > > grub_xfs_first_de(dir->data, > > > dirblock); > > > int entries = -1; > > > char *end = dirblock + dirblk_size; > > > + grub_uint32_t magic; > > > > > > numread = grub_xfs_read_file (dir, 0, 0, > > > blk << dirblk_log2, > > > @@ -912,6 +913,15 @@ grub_xfs_iterate_dir (grub_fshelp_node_t dir, > > > return 0; > > > } > > > > > > + /* > > > + * If this data block isn't actually part of the extent list > > > then > > > + * grub_xfs_read_file() returns a block of zeros. So if the > > > magic number > > > + * field is all zeros then this block should be skipped. > > > + */ > > > + magic = *(grub_uint32_t *)dirblock; > > > + if (!magic) > > > + continue; > > > + > > > /* > > > * Leaf and tail information are only in the data block if the > > > number > > > * of extents is 1. > > > -- > > > 2.43.0 > >
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